conio.c:

conio.c:
* create a CSRSS_SCREEN_BUFFER object before TuiInit/GuiInit
  -> required for variable screen buffer sizes
* improve error handling in CsrCreateScreenBuffer

guiconsole.c:
* directly store WindowSize in CSRSS_CONSOLE struct
* read ScreenBufferSize value from registry and store result in CSRSS_SCREEN_BUFFER
* use default values for ScreenBufferSize / WindowSize

tuiconsole.c:
* set screenbuffer size to size of physical console size in init

svn path=/trunk/; revision=23031